Gear pump



United States Patent O 2 Claims ABSTRACT F THE DISCLOSURE A gear pumphaving a pair of interengaging gears rotatable in a chamber, two inletports for admitting uid from two separate sources and in a set ratiointo the chamber, each of the gear wheels serving to impel uid from oneof the sources toward an outlet port, the uid from the two inlet portsbeing combined at the outlet port.

Gear pumps usually include two inter-engageable gear wheels which rotatein a pump chamber. The two wheels serve to draw fluid from a singlechamber inlet port and to expel it through a chamber outlet port. Gearpumps have often been employed for purposes in which it is desirable topump fluids from two separate sources. Where gear pumps have been soused, it has usually `been necessary to employ two pumps, each connectedto one of the separate sources. Such use of two pumps has presenteddisadvantages, both with respect to increased costs and increased spacerequirements.

Attempts have been made to direct the fluid from the two separatesources into the inlet port of a single pump. This fails to provide anadequate degree of control over the pumping operation. In particular, ithas not been possible to pump the uids from the separate sources in afixed ratio. Since the uids pumped may differ in resistance to the pumpsuction, an undesirably large proportion of one fluid may be pumped ascompared to the amount of the other fluid being pumped.

Gear pumps have been employed for pumping cooling oil to the brakes ofan automotive vehicle such as a tractor. The oil employed has often beendrawn from the torque converter scavenge sump of the vehicle. Such oilhas not always provided adequate cooling of the 'brakes when overheated.It has, therefore, been considered desirable to provide cooling oil in axed ratio `from two separate sources. The cost of providing additionalcooling oil has been prohibitive because of the need for a second pumpand the provision of space for two pumps.

The present invention is designed to overcome the above discussedproblems of the prior art. The advantages of the invention will becomeapparent to one skilled in the art trom the following description whenread in conjunction with the accompanying drawing which is a medialcross sectional fview of a pump constructed in accordance with theinvention.

In the drawing, there is shown a gear pump which embodies the presentinvention. The pump 10 provides a housing 12 which denes a chamber 14.The chamber 14 has an outlet port 16.

Mounted within the chamber 14 are a pair of gears 20 and 22. Each of thegears 20 and 22 has teeth 24 which define cavities 25 therebetween. Thegear 20 is rotatable in a clockwise direction while the gear 22 isrotatable in a counterclockwise direction. The gears are positioned forinter-engagement of their teeth approximately at the center of thechamber 14. The teeth 24, when disengaged, pass in close proximity tothe wall surface 26 of the chamber 14.

Two inlet ports 32 and 34 are disposed at opposite sides of the chamber14.

In order that more lluid will be drawn by the pump through one inletthan through the other, an inlet ratio bypass passageway is provided at36. It extends between inlet passage 32, as at 38, to a point 40 in thegear chamber upstream of the point where inlet 34 enters.

In the operation of the pump 10, fluid from a first source enters thechamber 14 through the passageway 32. Such fluid is impelled by therotating gear 20 through the chamber 14 and through the outlet port 16.

Fluid from a second source similarly enters the chamber 14 through theinlet passageway 34. This uid is impelled by the gear 22 toward andthrough the outlet port 16. Because of the bypass 36, some uid frominlet 32 ows to gear 22 and is propelled by it toward the outlet. Thisreduces the capacity of gear 22 to receive and transfer uid from inlet34.

The bypass or ratio-change passageway 36 provides a means for increasingthe amount of fluid admitted from the passageway 32 as compared to theamount of fluid admitted from the passageway 34. The size of thepassageway is designed to provide the desired ratio of ow from twosources and the ratio will remain substantially constant at differentpump speeds since the pump is of bsometric design between each inlet andthe outlet.

The pump may be employed yfor such purposes as the provision of coolingoil to the brakes of a tractor. It might thus be -used to scavenge thetorque converter by sucking oil and air from the latter through theinlet passageway 34. At the same time, oil from a separate reservoirmight be drawn through the inlet passageway 32. Such separate reservoirmight, for example, be the bevel gear case sump. The oil from the twosources would then be combined at the outlet 16 in a set ratio for usefor brake cooling purposes.

The use of the pump provides savings in both cost and space requirementsas compared to the use of two separate pumps for pumping the uids fromthe two separate sources.

We claim:

1. A gear pump comprising:

(a) a housing defining a chamber having a iluid outlet port;

(b) a pair of inter-meshing -gears rotatable in said chamber and eachadapted to impel uid toward said outlet port;

(c) means defining a rst fluid inlet port for said chamber and beingadapted to introduce fluid between the teeth of one of said gears; and

(d) means defining a second iiud inlet port for said chamber and beingadapted to introduce iiuid between the teeth of the other of said gears,said inlet ports being located at opposite sides respectively of saidchamber, means to increase the rate 0f flow of uid introduced Ibetweenthe teeth of one of said gears as compared to the rate of flow of fluidintroduced between the teeth of the other of said gears, said meanscomprising a ratio-change passageway arranged to receive tluid from oneinlet passageway and to direct it to the gear adjacent the other inletpassageway.

3 4 2. A pump in accordance with claim 1 in which the 2,944,487 7/ 1960Walsh 103-7 passageway directs uid to the gear prior to the direc-3,018,641 1/ 1962 Carpigiani. tion of uid thereto by said otherpassageway. 3,080,819 3/ 1963 Mayes.

3,137,137 6/1964 Klle ..-103-7 X References Cited 5 3,242,867 3/1966Mosbacher 103--126 X 1 631 591 FTES PATENTS 103 7 DONLEY J. STOCKING,Primary Examiner.

1 1,687,523 10/1928 Stande. WARREN J. KRAUSS, ASSSaZ Examiner. 1,902,3463/1933 Vogt. 2,301,496 11/1942 Aldrich 10s-2X 10 103 126 7 U-S- Cl- X-R-2,820,416 1/ 1958 Compton.

